Vertex Relocation for Efficient Terrain Rendering

초록

A variety of level-of-detail techniques using mipmap hierarchy have been proposed to render the massive terrain datasets in realtime. However, even with these techniques, recent giga-triangle or giga-texel sized datasets exceed the capability of graphics hardware. As a result, inaccurate geometry representation may occur due to oversimplification by using low detail level. We propose vertex relocation using bias map that represents more accurate scene than using equivalent detail level of mipmap. Most of the geometry artifacts such as geo-popping appear at the position of rough surface especially when low detail level is involved. To reduce these artifacts, we introduce the idea of both attraction and elastic force concept to compute the vertices’ movement. Each texel of elevation data may pull adjacent vertices by the attraction force which corresponds to its roughness. However, strong attraction force may overlap some vertices in a point. To reduce the overlapping problem, we apply the idea of elastic force between a vertex and its neighbors. The elastic force between vertex and its neighbor will push each other if they are close. Computing each vertex’s movement using both the attraction and the elastic force can produce a biased distribution of vertices. These vertices may sample the rough area finely and the smooth area coarsely. As a result, our method more efficiently visualizes terrain image than the mipmap hierarchy with low detail level.